Up grading power amp... Mono blocks or stereo amp?

I am thinking of upgrading my Rogue Audio ST-90 power amp.
My System: Rogue Audio Persious Pre amp, the st-90 powere amp, Krell SACD Standard CD player, Pro-ject 10 Turntable w/ Shelter MK II cartridge, Straight wire Interconects and Speaker cables, And B&W 803s speakers. This amp is nice but I think I could get an amp that is more quite, richer, and a bit more powerful. I was thinking about the Rogue Mono Blocks. What are the advantages/disadvantages of Mono Blocks versus a stereo amp? And yes, I want to stay w/ tubes.
Doug - the Rogue 150's are excellent monos and will be a very nice upgrade for you. They are dead quiet, have great presence and will give you very good, controlled, pitch precise low frequencies - something a lot of tube amps do not do well. The reasons some people shy away from mono amps are needing two amp stands, power cords, wall outlets, etc. ENJOY!
Advantages/disadvantages of monos vs. stereo amps are: Advantage Mono: Better seperation and isolation per channel. Advantage Stereo: Cost.
Now this may seem simple, but I currently replaced my $12K monoblock amps with a $10K stereo amp that just plain sounds better.

In your price range though, I would think that you could find a nice pair of Quicksilver V4 monoblocks that should do all that you ask and be a nice upgrade from the Rogue.



You will see why monoblocks are MUCH better

All The Best
I love my Rogue Audio 150 monos with my RA 99 pre amp pushing my Martin Logan SL3's. Its not good....Its great. Don't let the price fool you.These baby's rock with the best of them.
If you have space in front of your hi-fi setup two monos are always better than a stereo amp
Long signal cable (balanced are better) but short speaker cables
>>two monos are always better than a stereo amp<<

Not true at all.

There are many excellent stereo amps and an equal number of poor mono blocks.

Separate chassis does not guarantee anything except the requirement of an extra power cord.
Best thing about mono's is if one breaks down you still have one left to drive a center channel and you can use the other as a more effective boat anchor. The only reason I got big mono's is that they are still smaller than a comparable stereo amp - I'm not they guy that got sand kicked into his face by Charles Atlas, you'd probably need a crane to haul around a 160wt stereo tube amp. :-)
>> There are many excellent stereo amps and an equal number of poor mono blocks << (Audiofeil)

Obviously I was meaning "at the same quality level"
Everyone knows there are poor monos and good stereo amps!
But when you have the same quality level .. imho .. two monos are "always" better than the equal stereo amp
I think that a stereo amp can sound every bit as good as a monoblock amp of similar "quality" - that most of the "advantage" is theoretical with a little bit of "marketing" thrown in. But monos do help at keeping speaker cables very short, which is not a bad thing.
The primary argument for monoblocks other than shorter speaker cables (which by itself is a pretty important thing) is that there are no shared power supplies. An amplifier that has separate internal power supplies will be described as 'dual mono', but most stereo power amps do have shared supplies. In most stereo amplifiers, the incentive is price, as the chassis is often the most expensive part, followed by the power transformers.

Conversely, monoblocks are usually built to a higher standard as cost plays less of a role.

Overall these are generalizations, but good to keep in mind when looking at a specific product. They often are helpful in guiding one to an audition, but the audition is really the bottom line.

Atmasphere...Another important advantage of monoblocks, at least for high power units, is that they are not too heavy to pick up! That, and the short speaker wires is why I have monoblocks.

I think that the shared power supply thing is a bum rap, at least for the amps I have owned. It is usually only the transformer which is shared...each channel gets its own capacitors which will continue to run the amp for several seconds after its ac power is removed. One trick to help amps with so-so power supplies is to run one channel inverted, so as to even out the draw on plus and minus rail voltages. Some amps (the old dynaco ST120 is one) are spec'd for power with one channel inverted.
Eldartford, in a power supply with plenty of capacitance the caps are only charging at the peak of the AC input from the wall. At this point the rectifiers turn on and off (commutate) only at the peaks. So you have a spike that is riding on the top of the AC waveform from the wall.

Double the current and the spike is bigger- more noise will be present in the power transformer core. In addition, power drawn from one channel can lower the output voltage of the power transformer secondaries due to the internal DC resistance. This can affect the other channel (slightly). If *both* channels are drawing a lot of current, the voltage sags more. Its not a bum rap, its just what is.

A designer of a stereo amp has to consider these things. Its not really a problem in a monoblock.